1. Field of the Invention
The present invention relates generally to apparatuses for an internal combustion engine and particularly to a high-pressure fuel supply apparatus.
2. Description of the Related Art
Recently, in spark-ignition engines such as gasoline engines, the technologies of direct injection internal combustion engines have been developed to improve fuel consumption and emission gas performance thereof by supplying fuel under pressure by a high-pressure pump and directly injecting the pressurized fuel into a combustion chamber.
To directly injecting fuel into the combustion chamber as mentioned above, the high-pressurized fuel is handled. This needs a high-pressure fuel supply apparatus. Proposals are made for such technologies.
Japanese Patent No. 3836399 intends to provide a fuel apparatus, for an internal combustion engine, of a type including a fuel container; a fuel pump; a fuel collecting passage adapted to receive fuel supplied thereto by the fuel pump; a valve device capable of controlling pressure in the fuel collecting passage; and a fuel injection device capable of allowing fuel to reach inside a combustion chamber of the engine. This fuel apparatus is characterized by the following. The valve device is formed to be closed in a non-operative state if operation pressure in at least the fuel collecting passage is normal. The valve device includes a pre-load device, which biases a valve element in a closing direction. The pre-load device is formed so that the valve device is opened in a non-operated state if the pressure in the fuel collecting passage exceeds a prescribed value. An opening pressure of the valve device in the non-operative state is set to a level lower than a maximally allowable functional pressure of the fuel injection device.
JP-A-2004-28037 intends to provide a high-pressure fuel supply apparatus that includes a high-pressure fuel supply apparatus for supplying under pressure fuel pumped from a low-pressure fuel pump to a common rail by a high-pressure fuel pump and further supplying the pressurized fuel to an injector for directly injecting the fuel in the common rail into a combustion chamber; a pressure control valve for controlling pressure in the common rail by returning fuel to the low-pressure side when the pressure increases to a predetermined value or more; a device for detecting the pressure in the common rail; and a control apparatus for controlling the pressure in the common rail.
This high-pressure fuel supply apparatus is characterized in that when the high-pressure fuel supply apparatus or a control apparatus thereof causes malfunction so that the pressure in the common rail increases, the pressure in the common rail does not exceed the maximum possible pressure for injector opening of the injector.
Japanese patent No. 3972823 intends to provide a pressure-accumulating type fuel injection apparatus that accumulates in a common rail high-pressure fuel supplied under pressure by a fuel supply pump rotatably driven by an engine and injects and supplies the high-pressure fuel into a cylinder of the engine via an injector, and that includes a pressure safety valve that opens to suppress the fuel pressure in the common rail to a limit set pressure or lower when the fuel pressure in the common rail exceeds the limit set pressure. This fuel injection apparatus is characterized by including fuel pressure detecting means for detecting the fuel pressure in the common rail; and an engine control apparatus that controls the engine to avoid an abnormal high-pressure state occurring continuously for a predetermined time, the abnormal high-pressure state being such that the fuel pressure in the common rail detected by the fuel pressure detecting means exceeds a pump-use allowable zone affecting the lowering of reliability of the fuel supply pump or an injector-use allowable zone affecting the lowering of reliability of the injector.